This is a cobweb/comb-footed spider in the family Theridiidae. Like the vast majority of spiders, these have venom glands and thus at least technically can be considered venomous (see the 'sticky' on spider bites at the top of this forum). However, this one is not dangerous to humans. The only medically significant spiders in this family in the US are the widow spiders in the genus Latrodectus.